The research concerns the regulation of lipid metabolism in bacteria. The general approach is the isolation of mutants defective in either fatty acid or in phosphatide biosynthesis. We have designed specific selection techniques to isolate these mutants. Some of these mutants owe their phenotypes to lesions in the structural genes coding the enzymes of the pathway. Others of the mutants isolated should owe their phenotype to defects in regulatory genes. Both groups of mutants will be studied by an amalgam of genetic, enzymological and physiological techniques. These studies should ultimately provide an understanding of the molecular basis of this control. The structural gene lesions should also provide valuable information on the role of lipids in the assembly, structure, and function of biological membranes.